Example of an SQ file for Sysquake

Programs for Sysquake, called SQ files,
implement only the definition of figures and how the user can interact with them.
Sysquake provides itself support for synchronizing the figures, zoom, undo/redo,
and file management.

To show you how simple they can be, here is an SQ file which displays in the
same figure the magnitude of the frequency response of a continuous-time system,
and the same system sampled at a frequency you can manipulate with the mouse. The
Shannon theorem, which states that the sample frequency should be at least two times
higher than the bandwidth of the signal to be sampled in order to avoid loosing
information (i.e. there should be enough samples to catch the fastest changes),
and the aliasing which occurs when it is not verified, are much easier to
understand than with a mathematical demonstration or with static figures.